Not sure UC Express Services Interface is right for you and your organization? The technical overview describes the basics: how to use, where it fits in the architecture, and some requirements.

UC Express Services Interface provides CTI capabilities for CUCME to allow 3rd Party Applications to perform Call Monitoring, Control and Provisioning.
The UC Express Services Interface enables interaction between CUCME and 3rd Party Application Services to perform CTI functions, including Call Monitoring, Call Control and Call Provisioning with any SCCP end point. This new Interface includes two elements: 1) Native CTI protocol support within CME; 2) Java Function Library (referred to as the "UC Express Services SDK") that co-resides on an external server with the 3rd party application.
With UC Express Services Interface, CUCME can now be integrated with a variety of value added Unified Communication service applications, in either co-located or remote deployment scenarios, to elevate the value of CUCME from providing basic PBX functionality to supporting the critical Unified Communication services that are part of the users business process.